I'm sure I'll come up with better ones as I think about it, but the first one that pops into my mind is the dance scene in Young Frankenstein where they're doing "Putting on the Ritz". Even though I despise most Mel Brooks movies, the parts where the monster sings "PUUUHHHHIN AH DA RIIIIIIIIIIII!!!!!" never fails to crack me up.

Off the top of my head, the scene in Caddyshack where Al Czervick (Rodney) pulls up to the clubhouse and his friend is taking photos and he says, "Hey Wang! It's a parking lot! This is an exclusive club, Wang- don't tell em you're Jewish."